Covered drinking receptacles are old in the art; however, such drinking receptacles usually suffer from one or more drawbacks. This invention relates to a covered drinking cup which overcomes these drawbacks, and specfically relates to a covered drinking cup wherein the cover is rotatable about an axis generally parallel to the longitudinal axis of the handle upon actuation by a thumb-operated push lever.
Covering drinking cups serve several useful purposes. Initially, a cover over a drinking cup prevents the entry of unwanted material, such as dirt or the like, from entering the cup and contaminating the liquid contained therein. Secondly, a cover may serve to retain a degree of heat in the cup if the cup is used for hot liquids. Finally, a cover can serve to prevent sudden spillage of liquid contained in the cup when the cup is overturned. However, in order to provide flexibility to the user, a certain degradation in the tightness of the seal formed by the cover is lost in any cup. In the past, covered cups generally failed in this area, in that the cover did not adequately seal, or if the cover did adequately seal, the opening provided upon actuation of the cover mechanism was either awkward or of inadequate size to allow proper usage of the cup. Another common problem in covered cups is the failure to provide provision for venting the cup in the event a hot or ice-cold liquid was placed therein. The loss of heat from a hot fluid, or the gain of heat in a cool fluid, will cause the cover to be pulled inwardly in the first instance, or forced outwardly in the second instance. In the case of the hot fluid, the cover may become "stuck" to the cup by the vacuum formed therein, thus preventing use of the cup. In the case of the cold liquid, the cup cover will not seat properly as the expansion of the gas above the liquid as the liquid heats causes to cover to periodically become unseated. Therefore, it is appropriate to include a vent in any cover. The vent should be small enough so that normal drinking liquids will not pass through the vent in the event the cup overturns. Furthermore, the cover should be resiliently bound to the cup by spring action sufficiently strong to prevent the weight of the liquid from unseating the cover when it is in the closed position.
It was to meet and overcome these limitations that this invention was developed.